power_supply: Add voltage_ocv property and use it for max17042 driver

This adds a new sysfs file called 'voltage_ocv' which gives the
Open Circuit Voltage of the battery.

This property can be used for platform shutdown policies and
can be useful for initial capacity estimations.

Note: This patch is generated against linux-next branch.

Signed-off-by: Ramakrishna Pallala <ramakrishna.pallala@intel.com>
Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
diff --git a/drivers/power/max17042_battery.c b/drivers/power/max17042_battery.c
index 738648d..42c4be9 100644
--- a/drivers/power/max17042_battery.c
+++ b/drivers/power/max17042_battery.c
@@ -106,6 +106,7 @@
 	POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN,
 	POWER_SUPPLY_PROP_VOLTAGE_NOW,
 	POWER_SUPPLY_PROP_VOLTAGE_AVG,
+	POWER_SUPPLY_PROP_VOLTAGE_OCV,
 	POWER_SUPPLY_PROP_CAPACITY,
 	POWER_SUPPLY_PROP_CHARGE_FULL,
 	POWER_SUPPLY_PROP_TEMP,
@@ -172,6 +173,13 @@
 
 		val->intval = ret * 625 / 8;
 		break;
+	case POWER_SUPPLY_PROP_VOLTAGE_OCV:
+		ret = max17042_read_reg(chip->client, MAX17042_OCVInternal);
+		if (ret < 0)
+			return ret;
+
+		val->intval = ret * 625 / 8;
+		break;
 	case POWER_SUPPLY_PROP_CAPACITY:
 		ret = max17042_read_reg(chip->client, MAX17042_RepSOC);
 		if (ret < 0)